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Hey Hammond101, I don't think this is a good sign. I knew what I wanted to write but I wrote it backwards. My mind is starting to go, I hate getting old. Well at least you knew what I was asking and you answered my question. Thank you kindly for that.

Now here's another question. If an amp is designed for a 10% resistors and you use a 5% in its place and let's say down the road it drifts to +8%. Would it still be in spec for the amp even though it's out of spec for a 5% resistor. It would still be in range if it was a 10%.

(This message was last edited by roadhog96 at 07:59 PM, Mar 2nd, 2017)

I remember reading Jack Darr's book about 35 years ago. Jack was a practical man whose primary concern seem to be keeping gear operational. This was before the age of Internet forums where people discuss the nuances of biasing an amp for tone or which capacitors sound better.

Jack said that for many resistors in an amp, the actual value is not critical and the amp would still operate with a replacement resistance anywhere between one half and double the specified resistance. That's -50% to +100% tolerance.

Applying this philosophy to your typical Fender circuit, in a pinch you could send your client out on the stage with a 100K plate load resistor replaced with anything between 50K and 200K. Or the 3.3M reverb mixer resistor could be 1.8M or 6M. Preamp cathode resistors between 820 and 3K instead of 1500.

Hey, it's working! Yeah, it might not sound exactly the same but sound comes out and that's better than one that's silent.

Outside of filters like EQs where exact values are needed for proper operation, the reason for a manufacturer to use tight tolerance parts in all applications is so that each unit rolling off the line sounds exactly like its brother. We've all heard about an amp that just had IT and was special. Why can't they all have IT and be special? Consistency is good!

"Hey, it's working!" Back in the 70s and earlier, pretty much nobody paid attention to tube matching. Blow a tube--buy a tube. Remember those TV shop tube testers that were the size of a kitchen stove?

Oh yah I remember those tube testers. The local Drug store had one that I used when I blew a tube. They sold new ones that were stored in the bottom cabinet. Never heard of matching tubes back then.

I remember using a spare guitar cable to power an Bandmaster speaker cab for my Pro Reverb, never heard about speaker cable impedance. The 1/4" plugs fit the jacks and there was sound. Hey it worked and that's all that mattered back then.

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